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Lopes PKF, Costa SDO, Simino LADP, Chaves WF, Silva FA, Costa CL, Milanski M, Ignacio-Souza LM, Torsoni AS, Torsoni MA. Hypothalamic inflammation and the development of an obese phenotype induced by high-fat diet consumption is exacerbated in alpha7 nicotinic cholinergic receptor knockout mice. Food Res Int 2024; 176:113808. [PMID: 38163714 DOI: 10.1016/j.foodres.2023.113808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/27/2023] [Accepted: 12/02/2023] [Indexed: 01/03/2024]
Abstract
Hypothalamic inflammation and metabolic changes resulting from the consumption of high-fat diets have been linked to low grade inflammation and obesity. Inflammation impairs the hypothalamic expression of α7 nicotinic acetylcholine receptor (α7nAChR). The α7nAChR is described as the main component of the anti-inflammatory cholinergic pathway in different inflammation models. To assess whether the reduction in α7nAChR expression exacerbates hypothalamic inflammation induced by a high-fat diet (HFD), were used male and female global α7nAChR knockout mouse line in normal or high-fat diet for 4 weeks. Body weight gain, adiposity, glucose homeostasis, hypothalamic inflammation, food intake, and energy expenditure were evaluated. Insulin sensitivity was evaluated in neuronal cell culture. Consumption of an HFD for 4 weeks resulted in body weight gain and adiposity in male Chrna7-/- mice and the hypothalamus of male Chrna7-/- mice showed neuroinflammatory markers, with increased gene expression of pro-inflammatory cytokines and dysregulation in the nuclear factor kappa B pathway. Moreover, male Chrna7-/- mice consuming an HFD showed alterations in glucose homeostasis and serum of Chrna7-/- mice that consumed an HFD impaired insulin signalling in neuronal cell culture experiments. In general, female Chrna7-/- mice that consumed an HFD did not show the phenotypic and molecular changes found in male mice, indicating that there is sexual dimorphism in the analysed parameters. Thus, receptor deletion resulted in increased susceptibility to hypothalamic inflammation and metabolic damage associated with HFD consumption in male mice.
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Affiliation(s)
| | - Suleyma de Oliveira Costa
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil
| | - Laís A de Paula Simino
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil
| | - Wenicios Ferreira Chaves
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil
| | - Franciely Alves Silva
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil
| | - Caroline Lobo Costa
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil
| | - Marciane Milanski
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil; Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Brazil
| | - Leticia Martins Ignacio-Souza
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil; Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Brazil
| | - Adriana Souza Torsoni
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil; Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Brazil
| | - Marcio Alberto Torsoni
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Brazil; Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Brazil.
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García AP, Gaydou L, Pérez E, Barrantes FJ. Insulin resistance induced by long-term hyperinsulinemia abolishes the effects of acute insulin exposure on cell-surface nicotinic acetylcholine receptor levels and actin cytoskeleton morphology. Biochem Biophys Res Commun 2023; 685:149165. [PMID: 37922786 DOI: 10.1016/j.bbrc.2023.149165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023]
Abstract
Using CHO-K1/A5 cells, a clonal cell line that robustly expresses adult muscle-type nicotinic acetylcholine receptor (nAChR), we explored whether insulin resistance in these mammalian cells affects cell-surface expression of the nAChR, its endocytic internalization, and actin cytoskeleton integrity. Acute nanomolar insulin stimulation resulted in a slow increase in nAChR cell-surface levels, reaching maximum levels at ∼1 h. Long periods of insulin incubation caused CHO-K1/A5 cells to become insulin resistant, as previously observed with several other cell types. Furthermore, long-term insulin treatment abolished the effects of short-term insulin exposure on cell-surface nAChR levels, suggestive of a desensitization phenomenon. It also affected the kinetics of ligand-induced nAChR internalization. Since the integrity of the cortical actin cytoskeleton affects nAChR endocytosis, we also studied the effects of long-term insulin treatment on this meshwork. We found that it significantly affected the cortical actin morphology of CHO-K1/A5 cells and the response of the actin cytoskeleton to a subsequent short-term insulin stimulus. Overall, the present results show for the first time the effects of insulin signaling on cell-surface nAChR expression and actin cytoskeleton-associated internalization.
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Affiliation(s)
- Ana Paula García
- Laboratorio de Neurobiología Molecular, Instituto de Investigaciones Biomédicas (BIOMED) UCA-CONICET, Facultad de Ciencias Médicas, Universidad Católica de Argentina, Buenos Aires, Argentina; Instituto de Salud y Ambiente del Litoral (ISAL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral-CONICET, Santa Fe, Argentina
| | - Luisa Gaydou
- Instituto de Salud y Ambiente del Litoral (ISAL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral-CONICET, Santa Fe, Argentina; Departamento de Bioquímica Clínica y Cuantitativa, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Eugenia Pérez
- Laboratorio de Neurobiología Molecular, Instituto de Investigaciones Biomédicas (BIOMED) UCA-CONICET, Facultad de Ciencias Médicas, Universidad Católica de Argentina, Buenos Aires, Argentina
| | - Francisco J Barrantes
- Laboratorio de Neurobiología Molecular, Instituto de Investigaciones Biomédicas (BIOMED) UCA-CONICET, Facultad de Ciencias Médicas, Universidad Católica de Argentina, Buenos Aires, Argentina.
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Simino LAP, Baqueiro MN, Panzarin C, Lopes PKF, Góis MM, Simabuco FM, Ignácio-Souza LM, Milanski M, Ross MG, Desai M, Torsoni AS, Torsoni MA. Hypothalamic α7 nicotinic acetylcholine receptor (α7nAChR) is downregulated by TNFα-induced Let-7 overexpression driven by fatty acids. FASEB J 2023; 37:e23120. [PMID: 37527279 DOI: 10.1096/fj.202300439rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 07/10/2023] [Accepted: 07/19/2023] [Indexed: 08/03/2023]
Abstract
The α7nAChR is crucial to the anti-inflammatory reflex, and to the expression of neuropeptides that control food intake, but its expression can be decreased by environmental factors. We aimed to investigate whether microRNA modulation could be an underlying mechanism in the α7nAchR downregulation in mouse hypothalamus following a short-term exposure to an obesogenic diet. Bioinformatic analysis revealed Let-7 microRNAs as candidates to regulate Chrna7, which was confirmed by the luciferase assay. Mice exposed to an obesogenic diet for 3 days had increased Let-7a and decreased α7nAChR levels, accompanied by hypothalamic fatty acids and TNFα content. Hypothalamic neuronal cells exposed to fatty acids presented higher Let-7a and TNFα levels and lower Chrna7 expression, but when the cells were pre-treated with TLR4 inhibitor, Let-7a, TNFα, and Chrna7 were rescued to normal levels. Thus, the fatty acids overload trigger TNFα-induced Let-7 overexpression in hypothalamic neuronal cells, which negatively regulates α7nAChR, an event that can be related to hyperphagia and obesity predisposition in mice.
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Affiliation(s)
- Laís A P Simino
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Mayara N Baqueiro
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Carolina Panzarin
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Priscilla K F Lopes
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Mariana M Góis
- Multidisciplinary Laboratory of Food and Health (Labmas), School of Applied Sciences (FCA), University of Campinas (UNICAMP), Campinas, Brazil
| | - Fernando M Simabuco
- Multidisciplinary Laboratory of Food and Health (Labmas), School of Applied Sciences (FCA), University of Campinas (UNICAMP), Campinas, Brazil
| | - Letícia M Ignácio-Souza
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
- Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, Brazil
| | - Marciane Milanski
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
- Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, Brazil
| | - Michael G Ross
- The Lundquist Institute, David Geffen School of Medicine at Harbor - UCLA Medical Center, UCLA, Los Angeles, California, USA
| | - Mina Desai
- The Lundquist Institute, David Geffen School of Medicine at Harbor - UCLA Medical Center, UCLA, Los Angeles, California, USA
| | - Adriana S Torsoni
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
- Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, Brazil
| | - Marcio A Torsoni
- Laboratory of Metabolic Disorders (Labdime), School of Applied Sciences, University of Campinas (UNICAMP), Campinas, Brazil
- Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, Brazil
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Activation of α7nAChR by PNU282987 improves cognitive impairment through inhibiting oxidative stress and neuroinflammation in D-galactose induced aging via regulating α7nAChR/Nrf2/HO-1 signaling pathway. Exp Gerontol 2023; 175:112139. [PMID: 36898594 DOI: 10.1016/j.exger.2023.112139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/22/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023]
Abstract
Aging is an important risk factor for neurodegenerative diseases. The activation of α7 nicotinic acetylcholine receptor (α7nAChR) is involved in inflammation and cognition, but the specific role it plays in aging remains unknown. This study aimed to investigate the anti-aging effect of the activation of α7nAChR on aging rats and BV2 cells induced by D-galactose, as well as its potential mechanism. D-galactose induced an increase in the SA-β-Gal positive cells, expression of p16 and p21 in vivo and in vitro. α7nAChR selective agonist PNU282987 decreased levels of pro-inflammatory factors, MDA, and Aβ, enhanced SOD activity and levels of anti-inflammatory factor (IL10) in vivo. PNU282987 enhanced the expression of Arg1, decreased the expression of iNOS, IL1β and TNFα in vitro. PNU282987 upregulated the levels of α7nAChR, Nrf2 and HO-1 in vivo and in vitro. The results of Morris water maze and novel object recognition tests showed that PNU282987 improved cognitive impairment in aging rats. Furthermore, α7nAChR selective inhibitor methyllycaconitine (MLA) results were opposite with PNU282987. PNU282987 improves cognitive impairment through inhibiting oxidative stress and neuroinflammation in D-galactose induced aging via regulating the α7nAChR/Nrf2/HO-1 signaling pathway. Therefore, targeting the α7nAChR may be a viable therapeutic approach for anti-inflammaging and neurodegenerative diseases.
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